From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: When should ralloc.c be used? Date: Fri, 28 Oct 2016 09:03:00 -0400 Message-ID: References: <837f8znk8f.fsf@gnu.org> <83zilvm2ud.fsf@gnu.org> <83r377m0i8.fsf@gnu.org> <83eg36n6v5.fsf@gnu.org> <83shrl523p.fsf@gnu.org> <83eg354ux3.fsf@gnu.org> <4f0c2868-d408-a5c4-d5a8-90dae750eb33@dancol.org> <878tt9ggdk.fsf@ritchie.wxcvbn.org> <83k2cssypt.fsf@gnu.org> <6350b2df-fde9-e716-d279-9f29438f8ee5@dancol.org> <83d1ikswsf.fsf@gnu.org> <87vawcem79.fsf@ritchie.wxcvbn.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1477659893 28297 195.159.176.226 (28 Oct 2016 13:04:53 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 28 Oct 2016 13:04:53 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Oct 28 15:04:49 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1c06px-0006El-Ht for ged-emacs-devel@m.gmane.org; Fri, 28 Oct 2016 15:04:45 +0200 Original-Received: from localhost ([::1]:49058 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c06pz-0005DD-SE for ged-emacs-devel@m.gmane.org; Fri, 28 Oct 2016 09:04:47 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:45540) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c06pE-0005Ct-Os for emacs-devel@gnu.org; Fri, 28 Oct 2016 09:04:03 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c06p9-0000HI-RV for emacs-devel@gnu.org; Fri, 28 Oct 2016 09:04:00 -0400 Original-Received: from [195.159.176.226] (port=37077 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1c06p9-0000Gd-LO for emacs-devel@gnu.org; Fri, 28 Oct 2016 09:03:55 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1c06of-00052j-HY for emacs-devel@gnu.org; Fri, 28 Oct 2016 15:03:25 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 14 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:Rdg/4WA8YNWxJ7zzwNIL7qro8c0= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 195.159.176.226 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:208941 Archived-At: > I wouldn't have thought that PROT_NONE vs PROT_READ|PROT_WRITE would > have changed anything here, but on *some* OSes it does, however it is > not portable. At least OpenBSD doesn't behave like what you describe. Are you sure? Can you point to concrete evidence? Not that's it's important (using a hard-coded number like 2GB wouldn't work, so we'd more likely use something like w32heap.c's "pre-allocate double the size", which doesn't suffer from that problem anyway and still guarantees efficient behavior when growing a buffer progressively from 1B to 100GB). Stefan